State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
J Genet Genomics. 2011 Feb;38(2):55-61. doi: 10.1016/j.jcg.2011.01.002. Epub 2011 Feb 23.
Nuclear envelope proteins have important roles in chromatin organization and signal-dependent transcriptional regulation. A previous study reported that the inner nuclear membrane protein, Otefin (Ote), was essential for germline stem cell (GSC) maintenance via interaction with Smad complex. The interaction of Ote with the Smad complex recruits the bam locus to the nuclear periphery and subsequently results in bam transcriptional silencing, revealing that nuclear peripheral localization is essential for bam gene regulation. However, it remains unknown whether the nuclear peripheral localization is sufficient for bam silencing. To address this issue, we have established a tethering system, in which the Gal4 DNA binding domain (DBD) of the Flag:Gal4 DBD:Ote▵LEM fusion protein physically interacts with the Gal4 binding sites upstream of bamP-gfp to artificially recruit the reporter gene gfp to the nuclear membrane. Our data demonstrated that the nuclear peripheral localization seemed to affect the expression of the target naked gene in S2 cells. By contrast, in Drosophila germ cells, the nuclear membrane localization was not sufficient for gene silencing.
核膜蛋白在染色质组织和信号依赖性转录调控中具有重要作用。先前的研究报道，核内膜蛋白 Otefin（Ote）通过与 Smad 复合物相互作用，对于生殖干细胞（GSC）的维持是必需的。Ote 与 Smad 复合物的相互作用将 bam 基因座募集到核周，并随后导致 bam 转录沉默，表明核周定位对于 bam 基因调控是必需的。然而，核周定位是否足以沉默 bam 基因仍然未知。为了解决这个问题，我们建立了一个 tethering 系统，其中 Flag:Gal4 DBD:Ote▵LEM 融合蛋白的 Gal4 DNA 结合域（DBD）与 bamP-gfp 上游的 Gal4 结合位点物理相互作用，从而人为地将报告基因 gfp 募集到核膜上。我们的数据表明，核周定位似乎影响了 S2 细胞中靶基因的表达。相比之下，在果蝇生殖细胞中，核膜定位不足以沉默基因。
